This study is a phase I/IIB evaluation of the safety and potential antiviral activity of prednisone in the setting of AIDS-associated wasting syndrome. Because of anecdotal success with corticosteroid therapy in this setting and because of the evidence that there is a paradoxical immune activation state associated with idiopathic wasting, we are exploring the immunologic and virologic effects of prednisone in patients who have AIDS and unexplained weight loss. We are also following patients closely in order to evaluate the safety of this therapy - including blood cell counts, electrolytes, and serial physical and ophthalmologic examinations. Thus far, seven patients have been screened and four have been enrolled into the trial. One patient has completed the three month trial but has chosen, after discussions with his primary physicians, to remain on prednisone. All four participants have had clinical improvement with stable or increasing weight. All four have had a downward trend, to varying degrees, in HIV load (quantitative plasma virus) with minimal or no change in CD4 counts. There have been no unexpected adverse effects or new opportunistic infections during the trial thus far. The current plan is to continue enrollment up to approximately 25 patients. Later studies may include rechallenging these participants a second time with high doses of prednisone or comparing the effects of this intervention with other experimental appetite stimulants or compounds which promote weight gain.